Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
The mass production of products has led to many innovations over the years. Substantial developments have been made in the industrial handling of various materials and items, particularly in the area of robotics. For example, various types of robotics and other automated systems are now used in order to “pick and place” items during many manufacturing and other materials handling processes. Such robotics and other systems can include robot arms that, for example, grip, lift and/or place an item as part of a designated process. Of course, other manipulations and materials handling techniques can also be accomplished by way of such robotics or other automated systems. Despite many advances over the years in this field, there are limitations as to what can be handled in such a manner.
Conventional robotic grippers typically use either suction or a combination of large normal forces and fine control with mechanical actuation in order to grip objects. Such techniques have several drawbacks. For example, the use of suction tends to require smooth, clean, dry and generally flat surfaces, which limits the types and conditions of objects that can be gripped. Suction also tends to require a lot of power for the pumps and is prone to leaks at any location on a vacuum or low pressure seal, with a resulting loss of suction being potentially catastrophic. The use of mechanical actuation often requires large normal or “crushing” forces against an object, and also tends to limit the ability to robotically grip fragile or delicate objects. Producing large forces also increases the cost of mechanical actuation. Mechanical pumps and conventional mechanical actuation with large crushing forces also often require substantial weight, which is a major disadvantage for some applications, such as the end of a robot arm where added mass must be supported. Furthermore, even when used with sturdy objects, robotic arms, mechanical claws and the like can still leave damaging marks on the surface of the object itself.
Alternative techniques for handling items and materials via non-permanent and/or reversible attachment may be employed. Chemical adhesives can leave residues and tend to attract dust and other debris that reduce effectiveness. Chemical adhesives can also require a significant amount of added force to undo or overcome a grip or attachment to an object once such a chemical adhesive grip or attachment is applied, since the gripping interaction and force is typically not reversible in such instances. Another approach to providing an attachment to an item involves the use of fasteners such as nails, screws, adhesive binding, rope, twine, and so on. However, similar to chemical adhesives, such fasteners are typically not readily detachable and therefore the attachment may not be reversible without an additional undertaking, and may lead to damage to the item or substrate.
Other approaches to non-permanent and/or reversible attachment of an object to a substrate may rely on van der Waals forces. These forces, which are exploited by natural geckos and more recent “artificial gecko” systems often require the use of a mechanical smoothing (pressure) force when applied to a substrate in order to induce the intimate contact, and as such these systems are typically not well suited to sustain large loads over long periods of time.